siegert



(No M00101.) 2 SheetsSheet 1.

H. E. 0. SIEGERT. FIRE GRATE.

No. 000,070. Patented Mar. 22,1898.

IIIJI Ni'rED STATES" PATENT FFICE.

FIRE-G RATE.

SPECIFICATION forming part of Letters Patent No. 600,970, dated March 22, 1898. Application filed June 16,1897. Serial No- 641,049'. (No model.) Patented in GermanyMay 21, 1896, No. 92,503.

To aZZ whont it may concern:

Be it known that LHERMANN EMIL OTTO SIEGERT, a subject of the Emperor of Germany, and a resident of Murowana-Goslin, district 'of Rogasen, Posen, Germany, have invented certain new and useful Improvements in Fire-Grates, of which the following is a full and clear specification.

The invention has been patented in Ger many, No. 92,503, dated May 21, 1896.

Furnace-bars have heretofore generally been made so that the air-inlet passages between them are narrower 'toward the fire. This causes a compression or squeezing of the air before its admission to the fuel, more particularly so because the air is materially heated by the sides of the bars. This compression or squeezing has, again, the consequence that the air does not get into the fireplace with sufficient speed or in sufficient quantity. There is thus a lack of air and an insufficient or too late mixture of it with the already evolved but still unburned gases, and this latter defect is increased in that in the systems heretofore proposed little provision was made for an ample dividing up of the air for combustion admitted in broad compact layers. From all these reasons the combustion and the heat in the fireplace are insufficient and a large percentage of unburned gases and carbon particles escape unused into the chimney.

Figure 1 of the accompanying drawings is a plan of part of a fire-grate constructed according to this invention; Fig. 2, a vertical cross-section through some of the furnacebars, and Fig. 3 a side view of part of a bar.

In contradistinction to the usual form the essential point in the present grate consists in making the cross-sectional area of each passage increase in size from the bottom to gradually in thickness from the bottom to the top. They are pierced with deep oval or pearshaped holes 0 in their lower part and have slots 01 in their upper part, which slightly inthroughout the grate is produced.

crease in width downward. At the bottom they are tapered off toward one side, as shown at e. The said holes 0 and slots d are not opposite each other, but alternate in position relatively to each other. The shallow fu rnace-bars b are about triangular in section, thinner below, where they terminate with sharp corners I). These bars have no holes or slots, and they extend down about as far as the openings 61 extend downwardly in the bars a. At the top the shallow bars stand about one-fourth inch above the deep bars in order to prevent the fire-rake from catching in the slots (1 in the deep bars and doing damage to the upper parts of same. The distance m at the bottom between two deep bars may be equal to the sum of the two top spaces 00 between a shallow bar 6 and its two adjoining deep bars 06.

The action of this fire-grate is, as follows: The air for combustion enters below and between the rounded bottom edges a of the deep bars and is heated by these bars. At the same time this air is distributed or broken up by means of the oblong holes 0 in the deep bars, and an equalization of the temperature In the lower part of the grate is formed a reservoir, so to say, which gives off an even supply upward and gets accession of fresh air from below. In spite of'the expansion of the air by heat it is not compressed or squeezed, as the deep furnace-bars a decrease in thickness toward the top and thus afford broader airpassages. The same applies to the upper part of the heated air, which expands more and more, because the slots afford another increase of area to the air-passages. At the same time the shallow furnace-bars b and the slots 01 produce a great subdivision of the preheated air and an intimate and even mixture with the fuel and the gases evolved.

The ashes and clinkers are free to drop without hindering the air-supply, and this is favored by the width of the slots d increasing downward and by the slanting guiding bottom faces e of the slots. These latter also aid the air-inlet. The foregoing explains that there is a saving in fuel and a smokeless combustion. Lastly, it should be noted that in the case of small fireplaces-for instance, for house-stoves-it suffices to make the air-out let as large as theair-inlet, for in such cases the depth of the bars is not considerable, so that the air is not preheated and expanded much, nor will the air thus be compressed or squeezed. In such cases the slots and holes in the deep bars may sometimes be omitted, but in no case must the outlet area be smaller than the inlet area, as has hitherto been the defect in all grate systems.

I claim 1. In a fire-grate the combination of deep furnace-bars a decreasing in thickness from bottom to top and shallow intermediate furnace-bars b decreasing in thickness from top to bottom substantially as and for the purpose set forth.

2. In a fire-grate the combination of the deep furnace-bars a, decreasing in thickness from bottom to top and shallow intermediate HERMANN EMIL OTTO SIEGER'I.

\Vitnesses:

D. EDWARD CRANE, A. MEIssoN. 

